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1.
Proc Natl Acad Sci U S A ; 121(20): e2322688121, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38709925

RESUMO

Brain metastatic breast cancer is particularly lethal largely due to therapeutic resistance. Almost half of the patients with metastatic HER2-positive breast cancer develop brain metastases, representing a major clinical challenge. We previously described that cancer-associated fibroblasts are an important source of resistance in primary tumors. Here, we report that breast cancer brain metastasis stromal cell interactions in 3D cocultures induce therapeutic resistance to HER2-targeting agents, particularly to the small molecule inhibitor of HER2/EGFR neratinib. We investigated the underlying mechanisms using a synthetic Notch reporter system enabling the sorting of cancer cells that directly interact with stromal cells. We identified mucins and bulky glycoprotein synthesis as top-up-regulated genes and pathways by comparing the gene expression and chromatin profiles of stroma-contact and no-contact cancer cells before and after neratinib treatment. Glycoprotein gene signatures were also enriched in human brain metastases compared to primary tumors. We confirmed increased glycocalyx surrounding cocultures by immunofluorescence and showed that mucinase treatment increased sensitivity to neratinib by enabling a more efficient inhibition of EGFR/HER2 signaling in cancer cells. Overexpression of truncated MUC1 lacking the intracellular domain as a model of increased glycocalyx-induced resistance to neratinib both in cell culture and in experimental brain metastases in immunodeficient mice. Our results highlight the importance of glycoproteins as a resistance mechanism to HER2-targeting therapies in breast cancer brain metastases.


Assuntos
Neoplasias Encefálicas , Neoplasias da Mama , Resistencia a Medicamentos Antineoplásicos , Glicocálix , Quinolinas , Receptor ErbB-2 , Células Estromais , Humanos , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Feminino , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/genética , Receptor ErbB-2/metabolismo , Receptor ErbB-2/genética , Glicocálix/metabolismo , Animais , Linhagem Celular Tumoral , Células Estromais/metabolismo , Células Estromais/patologia , Quinolinas/farmacologia , Camundongos , Comunicação Celular , Técnicas de Cocultura , Mucina-1/metabolismo , Mucina-1/genética , Transdução de Sinais , Receptores ErbB/metabolismo , Receptores ErbB/antagonistas & inibidores
2.
Nature ; 584(7820): 291-297, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32728216

RESUMO

The majority of therapies that target individual proteins rely on specific activity-modulating interactions with the target protein-for example, enzyme inhibition or ligand blocking. However, several major classes of therapeutically relevant proteins have unknown or inaccessible activity profiles and so cannot be targeted by such strategies. Protein-degradation platforms such as proteolysis-targeting chimaeras (PROTACs)1,2 and others (for example, dTAGs3, Trim-Away4, chaperone-mediated autophagy targeting5 and SNIPERs6) have been developed for proteins that are typically difficult to target; however, these methods involve the manipulation of intracellular protein degradation machinery and are therefore fundamentally limited to proteins that contain cytosolic domains to which ligands can bind and recruit the requisite cellular components. Extracellular and membrane-associated proteins-the products of 40% of all protein-encoding genes7-are key agents in cancer, ageing-related diseases and autoimmune disorders8, and so a general strategy to selectively degrade these proteins has the potential to improve human health. Here we establish the targeted degradation of extracellular and membrane-associated proteins using conjugates that bind both a cell-surface lysosome-shuttling receptor and the extracellular domain of a target protein. These initial lysosome-targeting chimaeras, which we term LYTACs, consist of a small molecule or antibody fused to chemically synthesized glycopeptide ligands that are agonists of the cation-independent mannose-6-phosphate receptor (CI-M6PR). We use LYTACs to develop a CRISPR interference screen that reveals the biochemical pathway for CI-M6PR-mediated cargo internalization in cell lines, and uncover the exocyst complex as a previously unidentified-but essential-component of this pathway. We demonstrate the scope of this platform through the degradation of therapeutically relevant proteins, including apolipoprotein E4, epidermal growth factor receptor, CD71 and programmed death-ligand 1. Our results establish a modular strategy for directing secreted and membrane proteins for lysosomal degradation, with broad implications for biochemical research and for therapeutics.


Assuntos
Espaço Extracelular/metabolismo , Lisossomos/metabolismo , Proteínas de Membrana/metabolismo , Proteólise , Proteínas Recombinantes de Fusão/metabolismo , Animais , Anticorpos/química , Anticorpos/metabolismo , Antígenos CD/metabolismo , Apolipoproteína E4/metabolismo , Antígeno B7-H1/metabolismo , Sistemas CRISPR-Cas , Linhagem Celular , Receptores ErbB/metabolismo , Feminino , Glicopeptídeos/síntese química , Glicopeptídeos/metabolismo , Humanos , Ligantes , Proteínas de Membrana/química , Camundongos , Domínios Proteicos , Transporte Proteico , Receptor IGF Tipo 2/metabolismo , Receptores da Transferrina/metabolismo , Proteínas Recombinantes de Fusão/síntese química , Proteínas Recombinantes de Fusão/química , Solubilidade , Especificidade por Substrato
3.
Proc Natl Acad Sci U S A ; 120(11): e2215376120, 2023 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-36897988

RESUMO

The Siglecs (sialic acid-binding immunoglobulin-like lectins) are glycoimmune checkpoint receptors that suppress immune cell activation upon engagement of cognate sialoglycan ligands. The cellular drivers underlying Siglec ligand production on cancer cells are poorly understood. We find the MYC oncogene causally regulates Siglec ligand production to enable tumor immune evasion. A combination of glycomics and RNA-sequencing of mouse tumors revealed the MYC oncogene controls expression of the sialyltransferase St6galnac4 and induces a glycan known as disialyl-T. Using in vivo models and primary human leukemias, we find that disialyl-T functions as a "don't eat me" signal by engaging macrophage Siglec-E in mice or the human ortholog Siglec-7, thereby preventing cancer cell clearance. Combined high expression of MYC and ST6GALNAC4 identifies patients with high-risk cancers and reduced tumor myeloid infiltration. MYC therefore regulates glycosylation to enable tumor immune evasion. We conclude that disialyl-T is a glycoimmune checkpoint ligand. Thus, disialyl-T is a candidate for antibody-based checkpoint blockade, and the disialyl-T synthase ST6GALNAC4 is a potential enzyme target for small molecule-mediated immune therapy.


Assuntos
Neoplasias , Proteínas Proto-Oncogênicas c-myc , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico , Animais , Humanos , Camundongos , Antígenos CD/metabolismo , Ligantes , Macrófagos/metabolismo , Neoplasias/metabolismo , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo
4.
J Biol Chem ; 300(2): 105579, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38141764

RESUMO

Siglec-7 (sialic acid-binding immunoglobulin-like lectin 7) is a glycan-binding immune receptor that is emerging as a significant target of interest for cancer immunotherapy. The physiological ligands that bind Siglec-7, however, remain incompletely defined. In this study, we characterized the expression of Siglec-7 ligands on peripheral immune cell subsets and assessed whether Siglec-7 functionally regulates interactions between immune cells. We found that disialyl core 1 O-glycans are the major immune ligands for Siglec-7 and that these ligands are particularly highly expressed on naïve T-cells. Densely glycosylated sialomucins are the primary carriers of these glycans, in particular a glycoform of the cell-surface marker CD43. Biosynthesis of Siglec-7-binding glycans is dynamically controlled on different immune cell subsets through a genetic circuit involving the glycosyltransferase GCNT1. Siglec-7 blockade was found to increase activation of both primary T-cells and antigen-presenting dendritic cells in vitro, indicating that Siglec-7 binds T-cell glycans to regulate intraimmune signaling. Finally, we present evidence that Siglec-7 directly activates signaling pathways in T-cells, suggesting a new biological function for this receptor. These studies conclusively demonstrate the existence of a novel Siglec-7-mediated signaling axis that physiologically regulates T-cell activity. Going forward, our findings have significant implications for the design and implementation of therapies targeting immunoregulatory Siglec receptors.


Assuntos
Antígenos de Diferenciação Mielomonocítica , Ligantes , Ativação Linfocitária , Linfócitos T , Antígenos de Diferenciação Mielomonocítica/genética , Antígenos de Diferenciação Mielomonocítica/imunologia , Polaridade Celular/genética , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Polissacarídeos/metabolismo , Ligação Proteica , Transdução de Sinais , Linfócitos T/imunologia , Humanos
5.
Proc Natl Acad Sci U S A ; 119(39): e2117105119, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36122205

RESUMO

Mucins are functionally implicated in a range of human pathologies, including cystic fibrosis, influenza, bacterial endocarditis, gut dysbiosis, and cancer. These observations have motivated the study of mucin biosynthesis as well as the development of strategies for inhibition of mucin glycosylation. Mammalian pathways for mucin catabolism, however, have remained underexplored. The canonical view, derived from analysis of N-glycoproteins in human lysosomal storage disorders, is that glycan degradation and proteolysis occur sequentially. Here, we challenge this view by providing genetic and biochemical evidence supporting mammalian proteolysis of heavily O-glycosylated mucin domains without prior deglycosylation. Using activity screening coupled with mass spectrometry, we ascribed mucin-degrading activity in murine liver to the lysosomal protease cathepsin D. Glycoproteomics of substrates digested with purified human liver lysosomal cathepsin D provided direct evidence for proteolysis within densely O-glycosylated domains. Finally, knockout of cathepsin D in a murine model of the human lysosomal storage disorder neuronal ceroid lipofuscinosis 10 resulted in accumulation of mucins in liver-resident macrophages. Our findings imply that mucin-degrading activity is a component of endogenous pathways for glycoprotein catabolism in mammalian tissues.


Assuntos
Catepsina D , Lisossomos , Mucinas , Animais , Catepsina D/genética , Catepsina D/metabolismo , Glicoproteínas/metabolismo , Humanos , Lisossomos/enzimologia , Mamíferos/metabolismo , Camundongos , Mucinas/metabolismo , Polissacarídeos/metabolismo
6.
J Biol Chem ; 299(6): 104755, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37116708

RESUMO

The colony-stimulating factor 3 receptor (CSF3R) controls the growth of neutrophils, the most abundant type of white blood cell. In healthy neutrophils, signaling is dependent on CSF3R binding to its ligand, CSF3. A single amino acid mutation in CSF3R, T618I, instead allows for constitutive, ligand-independent cell growth and leads to a rare type of cancer called chronic neutrophilic leukemia. However, the disease mechanism is not well understood. Here, we investigated why this threonine to isoleucine substitution is the predominant mutation in chronic neutrophilic leukemia and how it leads to uncontrolled neutrophil growth. Using protein domain mapping, we demonstrated that the single CSF3R domain containing residue 618 is sufficient for ligand-independent activity. We then applied an unbiased mutational screening strategy focused on this domain and found that activating mutations are enriched at sites normally occupied by asparagine, threonine, and serine residues-the three amino acids which are commonly glycosylated. We confirmed glycosylation at multiple CSF3R residues by mass spectrometry, including the presence of GalNAc and Gal-GalNAc glycans at WT threonine 618. Using the same approach applied to other cell surface receptors, we identified an activating mutation, S489F, in the interleukin-31 receptor alpha chain. Combined, these results suggest a role for glycosylated hotspot residues in regulating receptor signaling, mutation of which can lead to ligand-independent, uncontrolled activity and human disease.


Assuntos
Leucemia Neutrofílica Crônica , Humanos , Leucemia Neutrofílica Crônica/diagnóstico , Leucemia Neutrofílica Crônica/genética , Leucemia Neutrofílica Crônica/metabolismo , Glicosilação , Ligantes , Mutação , Receptores de Fator Estimulador de Colônias/genética , Receptores de Fator Estimulador de Colônias/metabolismo , Treonina/metabolismo , Fatores Estimuladores de Colônias/genética , Fatores Estimuladores de Colônias/metabolismo
7.
Glycobiology ; 34(1)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-37815932

RESUMO

Galectin-3, well characterized as a glycan binding protein, has been identified as a putative RNA binding protein, possibly through participation in pre-mRNA maturation through interactions with splicosomes. Given recent developments with cell surface RNA biology, the putative dual-function nature of galectin-3 evokes a possible non-classical connection between glycobiology and RNA biology. However, with limited functional evidence of a direct RNA interaction, many molecular-level observations rely on affinity reagents and lack appropriate genetic controls. Thus, evidence of a direct interaction remains elusive. We demonstrate that antibodies raised to endogenous human galectin-3 can isolate RNA-protein crosslinks, but this activity remains insensitive to LGALS3 knock-out. Proteomic characterization of anti-galectin-3 IPs revealed enrichment of galectin-3, but high abundance of hnRNPA2B1, an abundant, well-characterized RNA-binding protein with weak homology to the N-terminal domain of galectin-3, in the isolate. Genetic ablation of HNRNPA2B1, but not LGALS3, eliminates the ability of the anti-galectin-3 antibodies to isolate RNA-protein crosslinks, implying either an indirect interaction or cross-reactivity. To address this, we introduced an epitope tag to the endogenous C-terminal locus of LGALS3. Isolation of the tagged galectin-3 failed to reveal any RNA-protein crosslinks. This result suggests that the galectin-3 does not directly interact with RNA and may be misidentified as an RNA-binding protein, at least in HeLa where the putative RNA associations were first identified. We encourage further investigation of this phenomenon employ gene deletions and, when possible, endogenous epitope tags to achieve the specificity required to evaluate potential interactions.


Assuntos
Galectina 3 , RNA , Humanos , Epitopos , Galectina 3/genética , Galectina 3/metabolismo , Galectinas/metabolismo , Proteômica , Proteínas de Ligação a RNA
8.
Proc Natl Acad Sci U S A ; 118(3)2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33431669

RESUMO

Inflammatory pathologies caused by phagocytes lead to numerous debilitating conditions, including chronic pain and blindness due to age-related macular degeneration. Many members of the sialic acid-binding immunoglobulin-like lectin (Siglec) family are immunoinhibitory receptors whose agonism is an attractive approach for antiinflammatory therapy. Here, we show that synthetic lipid-conjugated glycopolypeptides can insert into cell membranes and engage Siglec receptors in cis, leading to inhibitory signaling. Specifically, we construct a cis-binding agonist of Siglec-9 and show that it modulates mitogen-activated protein kinase (MAPK) signaling in reporter cell lines, immortalized macrophage and microglial cell lines, and primary human macrophages. Thus, these cis-binding agonists of Siglecs present a method for therapeutic suppression of immune cell reactivity.


Assuntos
Anti-Inflamatórios/química , Antígenos CD/química , Glicopeptídeos/genética , Inflamação/tratamento farmacológico , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/genética , Anti-Inflamatórios/metabolismo , Antígenos CD/genética , Glicopeptídeos/química , Humanos , Macrófagos/efeitos dos fármacos , Microglia/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Fagócitos/efeitos dos fármacos , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/química , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/metabolismo , Transdução de Sinais/efeitos dos fármacos
9.
Proc Natl Acad Sci U S A ; 118(5)2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33495350

RESUMO

Glyco-immune checkpoint receptors, molecules that inhibit immune cell activity following binding to glycosylated cell-surface antigens, are emerging as attractive targets for cancer immunotherapy. Defining biologically relevant ligands that bind and activate such receptors, however, has historically been a significant challenge. Here, we present a CRISPRi genomic screening strategy that allowed unbiased identification of the key genes required for cell-surface presentation of glycan ligands on leukemia cells that bind the glyco-immune checkpoint receptors Siglec-7 and Siglec-9. This approach revealed a selective interaction between Siglec-7 and the mucin-type glycoprotein CD43. Further work identified a specific N-terminal glycopeptide region of CD43 containing clusters of disialylated O-glycan tetrasaccharides that form specific Siglec-7 binding motifs. Knockout or blockade of CD43 in leukemia cells relieves Siglec-7-mediated inhibition of immune killing activity. This work identifies a potential target for immune checkpoint blockade therapy and represents a generalizable approach to dissection of glycan-receptor interactions in living cells.


Assuntos
Antígenos de Diferenciação Mielomonocítica/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Genoma Humano , Lectinas/metabolismo , Polissacarídeos/metabolismo , Motivos de Aminoácidos , Antígenos de Diferenciação Mielomonocítica/química , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Glicopeptídeos/metabolismo , Humanos , Sinapses Imunológicas/metabolismo , Células Matadoras Naturais/metabolismo , Lectinas/química , Leucossialina/química , Leucossialina/metabolismo , Ligantes , Ligação Proteica
10.
J Biol Chem ; 298(5): 101917, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35405095

RESUMO

Akkermansia muciniphila, a mucin-degrading microbe found in the human gut, is often associated with positive health outcomes. The abundance of A. muciniphila is modulated by the presence and accessibility of nutrients, which can be derived from diet or host glycoproteins. In particular, the ability to degrade host mucins, a class of proteins carrying densely O-glycosylated domains, provides a competitive advantage in the sustained colonization of niche mucosal environments. Although A. muciniphila is known to rely on mucins as a carbon and nitrogen source, the enzymatic machinery used by this microbe to process mucins in the gut is not yet fully characterized. Here, we focus on the mucin-selective metalloprotease, Amuc_0627 (AM0627), which is known to cleave between adjacent residues carrying truncated core 1 O-glycans. We showed that this enzyme is capable of degrading purified mucin 2 (MUC2), the major protein component of mucus in the gut. An X-ray crystal structure of AM0627 (1.9 Å resolution) revealed O-glycan-binding residues that are conserved between structurally characterized enzymes from the same family. We further rationalized the substrate cleavage motif using molecular modeling to identify nonconserved glycan-interacting residues. We conclude that mutagenesis of these residues resulted in altered substrate preferences down to the glycan level, providing insight into the structural determinants of O-glycan recognition.


Assuntos
Mucinas , Akkermansia/enzimologia , Akkermansia/genética , Humanos , Metaloproteases/metabolismo , Mucinas/metabolismo , Mutagênese , Verrucomicrobia
11.
Nat Methods ; 17(11): 1133-1138, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33106676

RESUMO

We report O-Pair Search, an approach to identify O-glycopeptides and localize O-glycosites. Using paired collision- and electron-based dissociation spectra, O-Pair Search identifies O-glycopeptides via an ion-indexed open modification search and localizes O-glycosites using graph theory and probability-based localization. O-Pair Search reduces search times more than 2,000-fold compared to current O-glycopeptide processing software, while defining O-glycosite localization confidence levels and generating more O-glycopeptide identifications. Beyond the mucin-type O-glycopeptides discussed here, O-Pair Search also accepts user-defined glycan databases, making it compatible with many types of O-glycosylation. O-Pair Search is freely available within the open-source MetaMorpheus platform at https://github.com/smith-chem-wisc/MetaMorpheus .


Assuntos
Glicopeptídeos , Proteômica/métodos , Espectrometria de Massas em Tandem , Bases de Dados de Proteínas , Glicopeptídeos/análise , Glicopeptídeos/química , Glicosilação , Proteômica/instrumentação , Software , Fluxo de Trabalho
12.
Br J Surg ; 110(12): 1774-1784, 2023 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-37758504

RESUMO

BACKGROUND: Hand trauma, comprising injuries to both the hand and wrist, affects over five million people per year in the NHS, resulting in 250 000 operations each year. Surgical site infection (SSI) following hand trauma surgery leads to significant morbidity. Triclosan-coated sutures may reduce SSI in major abdominal surgery but have never been tested in hand trauma. Feasibility needs to be ascertained before a definitive trial can be delivered in hand trauma. METHODS: A multicentre feasibility RCT of antimicrobial sutures versus standard sutures involving adults undergoing surgery for hand trauma to evaluate feasibility for a definitive trial. Secondary objectives were incidence of SSI in both groups, hand function measured with patient-reported outcome measures, health-related quality of life and change in employment. Randomization was performed on a 1:1 basis, stratified by age of the patient and whether the injury was open or closed, using a secure, centralized, online randomization service. Participants were blinded to allocation. RESULTS: 116 participants were recruited and randomized (60 intervention, 56 control). Of 227 screened, most were eligible (89.5 per cent), and most who were approached agreed to be included in the study (84.7 per cent). Retention was low: 57.5 per cent at 30 days, 52 per cent at 90 days and 45.1 per cent at 6 months. Incidence of SSI was >20 per cent in both groups. Hand function deteriorated after injury but recovered to near pre-injury levels during the study period. CONCLUSIONS: Risk of SSI after hand trauma is high. A definitive RCT of antimicrobial sutures in hand trauma surgery is feasible, if retention is improved. TRIAL REGISTRATION: ISRCTN10771059.


Assuntos
Anti-Infecciosos Locais , Anti-Infecciosos , Traumatismos da Mão , Adulto , Humanos , Anti-Infecciosos Locais/uso terapêutico , Punho/cirurgia , Qualidade de Vida , Havaí , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Infecção da Ferida Cirúrgica/etiologia , Traumatismos da Mão/cirurgia
13.
J Gen Intern Med ; 38(13): 2921-2927, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37126125

RESUMO

BACKGROUND: Appointment no shows are prevalent in safety-net healthcare systems. The efficacy and equitability of using predictive algorithms to selectively add resource-intensive live telephone outreach to standard automated reminders in such a setting is not known. OBJECTIVE: To determine if adding risk-driven telephone outreach to standard automated reminders can improve in-person primary care internal medicine clinic no show rates without worsening racial and ethnic show-rate disparities. DESIGN: Randomized controlled quality improvement initiative. PARTICIPANTS: Adult patients with an in-person appointment at a primary care internal medicine clinic in a safety-net healthcare system from 1/1/2022 to 8/24/2022. INTERVENTIONS: A random forest model that leveraged electronic health record data to predict appointment no show risk was internally trained and validated to ensure fair performance. Schedulers leveraged the model to place reminder calls to patients in the augmented care arm who had a predicted no show rate of 15% or higher. MAINE MEASURES: The primary outcome was no show rate stratified by race and ethnicity. KEY RESULTS: There were 5840 appointments with a predicted no show rate of 15% or higher. A total of 2858 had been randomized to the augmented care group and 2982 randomized to standard care. The augmented care group had a significantly lower no show rate than the standard care group (33% vs 36%, p < 0.01). There was a significant reduction in no show rates for Black patients (36% vs 42% respectively, p < 0.001) not reflected in white, non-Hispanic patients. CONCLUSIONS: In this randomized controlled quality improvement initiative, adding model-driven telephone outreach to standard automated reminders was associated with a significant reduction of in-person no show rates in a diverse primary care clinic. The initiative reduced no show disparities by predominantly improving access for Black patients.

14.
Nat Chem Biol ; 17(9): 937-946, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33767387

RESUMO

Selective protein degradation platforms have afforded new development opportunities for therapeutics and tools for biological inquiry. The first lysosome-targeting chimeras (LYTACs) targeted extracellular and membrane proteins for degradation by bridging a target protein to the cation-independent mannose-6-phosphate receptor (CI-M6PR). Here, we developed LYTACs that engage the asialoglycoprotein receptor (ASGPR), a liver-specific lysosome-targeting receptor, to degrade extracellular proteins in a cell-type-specific manner. We conjugated binders to a triantenerrary N-acetylgalactosamine (tri-GalNAc) motif that engages ASGPR to drive the downregulation of proteins. Degradation of epidermal growth factor receptor (EGFR) by GalNAc-LYTAC attenuated EGFR signaling compared to inhibition with an antibody. Furthermore, we demonstrated that a LYTAC consisting of a 3.4-kDa peptide binder linked to a tri-GalNAc ligand degrades integrins and reduces cancer cell proliferation. Degradation with a single tri-GalNAc ligand prompted site-specific conjugation on antibody scaffolds, which improved the pharmacokinetic profile of GalNAc-LYTACs in vivo. GalNAc-LYTACs thus represent an avenue for cell-type-restricted protein degradation.


Assuntos
Receptor de Asialoglicoproteína/metabolismo , Lisossomos/metabolismo , Acetilgalactosamina/metabolismo , Humanos , Células Tumorais Cultivadas
15.
Nat Chem Biol ; 17(3): 326-334, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33199915

RESUMO

Secreted polypeptides are a fundamental axis of intercellular and endocrine communication. However, a global understanding of the composition and dynamics of cellular secretomes in intact mammalian organisms has been lacking. Here, we introduce a proximity biotinylation strategy that enables labeling, detection and enrichment of secreted polypeptides in a cell type-selective manner in mice. We generate a proteomic atlas of hepatocyte, myocyte, pericyte and myeloid cell secretomes by direct purification of biotinylated secreted proteins from blood plasma. Our secretome dataset validates known cell type-protein pairs, reveals secreted polypeptides that distinguish between cell types and identifies new cellular sources for classical plasma proteins. Lastly, we uncover a dynamic and previously undescribed nutrient-dependent reprogramming of the hepatocyte secretome characterized by the increased unconventional secretion of the cytosolic enzyme betaine-homocysteine S-methyltransferase (BHMT). This secretome profiling strategy enables dynamic and cell type-specific dissection of the plasma proteome and the secreted polypeptides that mediate intercellular signaling.


Assuntos
Betaína-Homocisteína S-Metiltransferase/genética , Biotina/química , Proteínas Sanguíneas/genética , Hepatócitos/metabolismo , Proteoma/genética , Coloração e Rotulagem/métodos , Animais , Betaína-Homocisteína S-Metiltransferase/metabolismo , Biotina/administração & dosagem , Biotinilação , Proteínas Sanguíneas/metabolismo , Expressão Gênica , Células HEK293 , Hepatócitos/citologia , Humanos , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células Musculares/citologia , Células Musculares/metabolismo , Células Mieloides/citologia , Células Mieloides/metabolismo , Especificidade de Órgãos , Pericitos/citologia , Pericitos/metabolismo , Proteoma/metabolismo , Proteômica/métodos
16.
Mol Cell Proteomics ; 20: 100029, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33583771

RESUMO

Glycosylation is a prevalent, yet heterogeneous modification with a broad range of implications in molecular biology. This heterogeneity precludes enrichment strategies that can be universally beneficial for all glycan classes. Thus, choice of enrichment strategy has profound implications on experimental outcomes. Here we review common enrichment strategies used in modern mass spectrometry-based glycoproteomic experiments, including lectins and other affinity chromatographies, hydrophilic interaction chromatography and its derivatives, porous graphitic carbon, reversible and irreversible chemical coupling strategies, and chemical biology tools that often leverage bioorthogonal handles. Interest in glycoproteomics continues to surge as mass spectrometry instrumentation and software improve, so this review aims to help equip researchers with the necessary information to choose appropriate enrichment strategies that best complement these efforts.


Assuntos
Glicopeptídeos/análise , Glicoproteínas/análise , Animais , Cromatografia/métodos , Glicômica/métodos , Glicopeptídeos/química , Glicoproteínas/química , Glicosídeo Hidrolases/química , Grafite/química , Humanos , Lectinas/química , Espectrometria de Massas/métodos , Proteômica/métodos
17.
Proc Natl Acad Sci U S A ; 117(14): 7764-7775, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32205440

RESUMO

The cell surface proteome, the surfaceome, is the interface for engaging the extracellular space in normal and cancer cells. Here we apply quantitative proteomics of N-linked glycoproteins to reveal how a collection of some 700 surface proteins is dramatically remodeled in an isogenic breast epithelial cell line stably expressing any of six of the most prominent proliferative oncogenes, including the receptor tyrosine kinases, EGFR and HER2, and downstream signaling partners such as KRAS, BRAF, MEK, and AKT. We find that each oncogene has somewhat different surfaceomes, but the functions of these proteins are harmonized by common biological themes including up-regulation of nutrient transporters, down-regulation of adhesion molecules and tumor suppressing phosphatases, and alteration in immune modulators. Addition of a potent MEK inhibitor that blocks MAPK signaling brings each oncogene-induced surfaceome back to a common state reflecting the strong dependence of the oncogene on the MAPK pathway to propagate signaling. Cell surface protein capture is mediated by covalent tagging of surface glycans, yet current methods do not afford sequencing of intact glycopeptides. Thus, we complement the surfaceome data with whole cell glycoproteomics enabled by a recently developed technique called activated ion electron transfer dissociation (AI-ETD). We found massive oncogene-induced changes to the glycoproteome and differential increases in complex hybrid glycans, especially for KRAS and HER2 oncogenes. Overall, these studies provide a broad systems-level view of how specific driver oncogenes remodel the surfaceome and the glycoproteome in a cell autologous fashion, and suggest possible surface targets, and combinations thereof, for drug and biomarker discovery.


Assuntos
Neoplasias da Mama/genética , Glicoproteínas de Membrana/genética , Proteoma/genética , Proteômica , Biomarcadores Tumorais/genética , Mama/metabolismo , Mama/patologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Receptores ErbB/genética , Feminino , Glicoproteínas/genética , Humanos , MAP Quinase Quinase Quinases/genética , Proteína Oncogênica v-akt/genética , Oncogenes/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Receptor ErbB-2/genética , Transdução de Sinais/genética
18.
PLoS Genet ; 15(3): e1008037, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30856163

RESUMO

Microbes can be metabolically engineered to produce biofuels and biochemicals, but rerouting metabolic flux toward products is a major hurdle without a systems-level understanding of how cellular flux is controlled. To understand flux rerouting, we investigated a panel of Saccharomyces cerevisiae strains with progressive improvements in anaerobic fermentation of xylose, a sugar abundant in sustainable plant biomass used for biofuel production. We combined comparative transcriptomics, proteomics, and phosphoproteomics with network analysis to understand the physiology of improved anaerobic xylose fermentation. Our results show that upstream regulatory changes produce a suite of physiological effects that collectively impact the phenotype. Evolved strains show an unusual co-activation of Protein Kinase A (PKA) and Snf1, thus combining responses seen during feast on glucose and famine on non-preferred sugars. Surprisingly, these regulatory changes were required to mount the hypoxic response when cells were grown on xylose, revealing a previously unknown connection between sugar source and anaerobic response. Network analysis identified several downstream transcription factors that play a significant, but on their own minor, role in anaerobic xylose fermentation, consistent with the combinatorial effects of small-impact changes. We also discovered that different routes of PKA activation produce distinct phenotypes: deletion of the RAS/PKA inhibitor IRA2 promotes xylose growth and metabolism, whereas deletion of PKA inhibitor BCY1 decouples growth from metabolism to enable robust fermentation without division. Comparing phosphoproteomic changes across ira2Δ and bcy1Δ strains implicated regulatory changes linked to xylose-dependent growth versus metabolism. Together, our results present a picture of the metabolic logic behind anaerobic xylose flux and suggest that widespread cellular remodeling, rather than individual metabolic changes, is an important goal for metabolic engineering.


Assuntos
Saccharomyces cerevisiae/metabolismo , Xilose/metabolismo , Anaerobiose , Biocombustíveis , Biomassa , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Evolução Molecular Direcionada , Fermentação , Perfilação da Expressão Gênica , Genes Fúngicos , Glucose/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Engenharia Metabólica , Redes e Vias Metabólicas , Modelos Biológicos , Mutação , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteoma/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Biologia de Sistemas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
19.
Rheumatology (Oxford) ; 60(9): 4094-4102, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34469568

RESUMO

OBJECTIVE: Base of thumb OA (BTOA) is a common age-related disease that has a significant negative impact on quality of life, while little is known about the structure and pathways of interface services. Our aim was to assess disease burden, referral pathways, service structure and management pathways in UK interface services. METHODS: A structured questionnaire was carried out with a participating clinician at each centre to detail the local guidelines and management of BTOA. Five patients referred with BTOA were prospectively identified in each of 32 UK interface centres. RESULTS: Most centres (72%) had a local guideline and a standardized treatment regime consisting of education (100%), joint protection (100%), range of motion exercises (84%), strengthening exercises (88%), splintage (100%) and use of assistive devices (78%). No centre routinely offered a steroid injection at the first appointment and no centre had a specific threshold for offering an injection. Injection delivery was variable. Most patients had not been referred previously (82%). Most patients used analgesia (72%), but a minority of patients had been treated with a splint (46%), therapy (43%) and steroid injection (27%) prior to their latest attendance. CONCLUSION: Most BTOA patients newly referred to interface services have been treated with analgesics and have not received comprehensive multimodal intervention. The management of BTOA at interface services is standardized in terms of education, splintage and therapy. However, there is a lack of standardization in terms of both the threshold for, timing of and mode of delivery of injection therapy.


Assuntos
Articulações Carpometacarpais/fisiopatologia , Osteoartrite/terapia , Modalidades de Fisioterapia , Polegar/fisiopatologia , Idoso , Terapia por Exercício , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/fisiopatologia , Amplitude de Movimento Articular/fisiologia , Resultado do Tratamento , Reino Unido
20.
Mol Cell Proteomics ; 18(8 suppl 1): S193-S201, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31088857

RESUMO

Here we present IPSA, an innovative web-based spectrum annotator that visualizes and characterizes peptide tandem mass spectra. A tool for the scientific community, IPSA can visualize peptides collected using a wide variety of experimental and instrumental configurations. Annotated spectra are customizable via a selection of interactive features and can be exported as editable scalable vector graphics to aid in the production of publication-quality figures. Single spectra can be analyzed through provided web forms, whereas data for multiple peptide spectral matches can be uploaded using the Proteomics Standards Initiative file formats mzTab, mzIdentML, and mzML. Alternatively, peptide identifications and spectral data can be provided using generic file formats. IPSA provides supports for annotating spectra collecting using negative-mode ionization and facilitates the characterization of experimental MS/MS performance through the optional export of fragment ion statistics from one to many peptide spectral matches. This resource is made freely accessible at http://interactivepeptidespectralannotator.com, whereas the source code and user guides are available at https://github.com/coongroup/IPSA for private hosting or custom implementations.


Assuntos
Proteômica/métodos , Bases de Dados de Proteínas , Internet , Peptídeos/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Software , Espectrometria de Massas em Tandem
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